DEVELOPMENT AND APPLICATION OF A GIS TOOL TO EXTRACT AND ANALYZE DEM-DERIVED STREAM CHANNEL LONGITUDINAL PROFILES

Fluvial stream channel longitudinal profiles (“stream profiles”) have been recognized to represent evidence of fluvial systems working toward an equilibrium state balancing the drivers of climate, geology, tectonics, and base level. The authors have developed GIS tools to streamline and simplify the process of generating stream profiles from digital elevation models (DEMs) and mapping watershed features onto these profiles. These tools leverage raster and vector analysis tools included in ArcGIS software with open-source python modules to extract profiles and break them into segments, each segment characterized with different steepness and concavity values, separated by transitional reaches representing prominent breaks in slope (“knick zones”). Since the tools work in a GIS environment, the profile segments can be compared in map view with mapped geology or other layers displayed from disk or dynamic web map services.

Preliminary applications of these GIS tools using lidar-based and contour-based elevation datasets suggest that longitudinal stream profiles created from DEMs are robust across data resolution and elevation data creation method. These tools are being used to compare stream profiles across Laramide terranes.